Field of Invention
The invention relates to a touch display device and an on-cell touch display device.
Related Art
With the progress of technologies, various novel information devices are invented, such as cell phones, tablet computers, ultrabooks and GPS navigation devices. Generally, a keyboard and mouse are commonly used to manipulate the information device for inputting information. Besides, the touch control technology currently also becomes a popular manipulation method for the information device and brings an intuitive operation. Accordingly, a touch display device using the touch control technology can provide a friendly and intuitive interface for the input operation, and therefore users of all ages can manipulate the touch display device by fingers or a stylus.
A conventional touch display device includes a color filter (CF) substrate, a liquid crystal layer, a thin film transistor (TFT), a touch sensing structure and two upper and lower polarization plates. The liquid crystal layer is disposed between the CF substrate and the TFT substrate, and the touch sensing structure is disposed on the CF substrate. The lower polarization plate is disposed on the side of the TFT substrate away from the CF substrate, and the upper polarization plate is disposed on the touch sensing structure. Then, a cover glass is disposed on the upper polarization plate to form an on-cell touch display device.
Another conventional touch display device includes an organic light emitting diode (OLED) substrate, a touch sensing structure and an upper polarization plate. The touch sensing structure is disposed on the OLED substrate and the upper polarization plate is disposed on the touch sensing structure. Then, a cover glass is disposed on the upper polarization plate to form another on-cell touch display device.
The touch sensing structure is generally an electrode structure including a plurality of wire regions and touch sensing regions disposed alternately. The touch sensing region includes driving electrodes and sensing electrodes (the so-called Tx and Rx) and the wire region includes a plurality of wires connected to a touch control circuit. However, due to the reflectivity difference between the electrode patterns and the slits of the touch sensing region and wire region, the bright and dark fringes caused by different directions of the reflected lights are easily to be seen in a particular viewing angle (or under a blaze), resulting in a bad visibility (which means users will easily see the electrode patterns).
Therefore, it is an important subject to provide a touch display device whereby the bright and dark fringes caused by the different directions of the reflected lights can be reduced so as to enhance the visibility.